Alternating-current-commutator-motor regulating apparatus



Feb. 7, 1928. 1,658,662

W. WELSCH ALTERNATING CURRENT COMMUTATOR MOTOR REGULATING APPARATUSFiled Sept. 25, 1926 2 Sheets-Sheet 1 Fig. I.

Inventor- Wilhelm Welsch,

y Hi 5 ATTorne g.

Feb. 7, 1928.

w. wELscH ALTERNATING CURRENT COMMUTATOR MOTOR REGULATING APPARATUSFiled Sept. 25, 1926 2 Sheets- Sheet 2 Fig.8.

as /2 a4 Pi g. 9.

\e v 33 \a a2 \a Invenror" Wilhelm Welsch His Afforne ranged inpolyphase relation, i.

Patented Feb. 7, i928.

UNETEB Siisi'lii \VILZ-I-ZELI V'ELZSCH, OE IFIEDEESCEEONHAUSEN,GER-MANY, ASSIG-NOB TO GENERAL ELEC'IMZC COMPANY, A CORIGRATIQE QF NEWYORK.

ALTEENATING-CURREHT-CGMMUTATOR-MOTOR BEGULATING APPARATUS.

Application filed September 25, 1926, Serial No. 137,801, and. inGermany October 5, 1925.

My invention relates to alternating current commutator motor regulatingapparatus wherein such a motor has its secondary commutator windingprovided with adjust- 5 able brushes which are supplied with regulatingvoltages through an induction voltage regulator. In particular myinvention relates to such a combination wherein the adjustment of thebrushes and the adjust- ]0 ment of the voltage regulator is effectedsimultaneously to provide speed and power factor regulation and in whichthe same adjusting apparatus may be used for both directions of rotationof the commutator motor. Another feature of my invention is theprovision with such apparatus of load responsive speed compensatingmeans.

The features of my invention which are believed to be new and patentablewill be pointed out in the claims appended hereto. For a betterunderstanding of the invention, reference is made in the followingdescription to the accompanying drawing in which Fig. 1 represents apreferred arrangement of the electrical connections for the apparatorsof my invention, the physical embodiment of which is represented in Fig.8; Fig. illustrates the character of power factor compensation obtainedby brush displacement and by means of the voltage regulator for var louspositions of adjustment; Figs. 3 to 7 inclusive are vector diagramsrepresent ng the voltage vectors produced by the volt e regulator. andthat produced by brusn adjustment for various positions of theregulating apparatus; Fig. 9 is a cross section of the regulating deviceshown in Fig. 8; Fig. 10 is a more or less diagrammatic representationof this regulating de vice illustrating the load responsive speedcompensating feature between the voltage regulator and the brush yoke ofthe commutator motor; and Fig. llv shows brush displacement speed curvesfor different load conditions which will be referred to hereinafter.

The type of motor with which the invention has been illustrated hereinis a polyphase motor having its secondary rotor winding connected to acommutator.

In Figs. 1 and 8, 10 represents the primary stator member, and 11 therotary secondary commutated member. Bearing on the commutator is asingle set of brushes 12 are, three brushes per pair of poles for athree-phase rotor. These brushes are mounted on an adjustable brush yoke13 as shown in Fig. 8. let represents an induction voltage regulator orrotary transformer, as it is some times called. having primary windings15 and relatively adjustable secondary windings 16. The primary windingwhich is here shown connected in 3 is preferably placed on the rotarypart of this regulator in order to eliminate the necessity of two setsof slip rings. The primary winding is supplied at constant voltage fromthe same source as the primary l of the motor and may be connected atappropriate voltage taps 17 of the primary winding of the motorrepresented in Fig. l. The rotary transformer is connected as anauto-transformer to the brushes 12 of the motor so that by relative yrotating the primary and secondary windings of the induction regulatorthe voltage supplied therefrom to the commu tated winding may be variedcausing the motor to run below or above synchronous speed. The magnitudeand phase angle of the voltage supplied to the brushes from theregulator may be indicated by the length and direction of the dottedline 0-2 of Fig. l which is made of a constant voltage supplied by thewinding 15 and a relatively variable angle constant magnitude voltagesupplied by the winding 16. The sum O2 of these two voltages isimpressed upon the commutator brushes.

It is evident that the induction regulator is adjusted to vary thevoltage, a certain amount of phas con'ipensation may be provided therebyin certain positions. It is also possible to obtain phase compensationby displacement of the brushes, that is by a lag of the brushes relativeto the direction of rotation for super-synchronous operation and a leadof the brushes for sub-synchronous operation. Such compensation isdesirable and it may be obtained at all speeds including synchronism bya combination of the two methods just mentioned. This simultaneousadjustment of the speed and power factor compensation is obtained byproviding a mechanical coupling between the voltage regulator and thebrush yoke of the desired gear ratio and by properly positioning thebrushes with respect to the position of the voltage regulator as well asproper size relation between voltages O-l and 12.

An example of the relative compensation which may be supplied by voltageregulation and by brush displacement is illustrated in Fig. 2 where 12represents the position of a brush for super-synchronous operation, 12for synchronous operation, and 12 for sub-synchronous operation. Thecrosshatched sector outside the circle represents 1 the compensationobtained from the voltage regulator, it being the greatest in the zoneof synchronism. The area between the dotted line outside the circlerepresents the compensation obtained by brush displacement and it is amaximum at theeXtreme positions.

II" it is desired that the apparatus be designed to enable'the motor tooperate in difierent directions of rotation, it will be a necessaryaddition to reversing the rotating field or the motor to efiect also areversing of the compensating voltages. The phase compensation over thespeed range exemplified in Fig. 2 for both directions of rotation may beaccomplished without introducing complicationsin the regulatingapparatus in the manner now to be explained.

' ln'Figs. 3 to 7 inclusive, the large circle may be considered as'thecommutator or the motor which'is here assumed to be a twopole motor, and12 one of the commutator brushes.

In the smaller circles 01 indicates the tired voltage vector of thevoltage regulator supplied by winding 15; 12 the angu larly variablevoltage vector supplied by Winding 16, and O2 the resultant voltagevector of that phase of the regulator connected to the brush 12 underconsideration.

'O.3 is the speed or working component of I and 23 the the regulatorvoltage 02, compensating component. The mechanical transmission betweenthe voltage regulator and the brush yoke of the motor and. the relativepositions or the voltage regulator and brush yoke will be such as toproduce the results indicated. V

Fig. 3 corresponds to the super-synchronous operation in whichthecompensation is obtained exclusively by the laggingshitt of the brushes.The two voltages of the regulator are in phase. In the case or aboutone-half super-synchronous operation, as shown in Fig. 4 the regulatorhas been adjusted 9O electrical degrees and the brushes adjustedsomewhat less than half of this.

Here the compensation is obtained partially by the voltage differencebetween the vectors O1 and 02 and partially by a shifting of the brushesfrom the 45 position. It is seen that if vectors O1 and 0-2 were equal,their resultant would be on-the 45 line andcompensation would beproduced exclusively by the shift of the brush from.

. such 45 line.

In Fig. 5, which corresponds to synchrooperation.

nous operation, the induced voltage 0-3 is zero but these points havebeen separated slightly for the sake of clearness. The compensationrepresented by line 2-3 is on; tamed exclusively by, the difference inthe voltage vectors ofthe regulator which are now 180 out ct phase.Figs. 6 and 7 correspond to one-half sub-synchronous and 12-O.'-l,Fig.7, may be made greaterthan the angle 12O2, Fig;

Yfhile the induction regulator has been shifted 330 degrees, the brushyoke has been shifted less tl an 180 so that the gear ratio between theregulator and brush "yoke of the motor should be as 360 is to the angleof brush shift. or sli htl 'reater than'2:1

and furthermore, the voltage O'1 should be 7 reater than the volta e 12to the extent b b 2-3 in Fig. 5 corresponding to the amount ofcompensation desired speed.

Now, in order to reverse the directionof rotation of the motor and usethe same regulating apparatus for the opposite direction of rotation, itis only necessary to at synchronous reverse the phase rotation of themotor as V, and to shift the brushes 12 independentlyot the regulator tothe position corresponding to by means Oi the switch 18, Fig. 8,

12, 7. This may be done for example by the connection indicated in 'F1g. 8. Here the shafts 20 and 21 are separate sections.

lPart 20 has hand lever 22 secured thereto and part 21 has anotched-wheel 23 secured thereto. T The hand lever carries a latch 24which normally meshes with a notch in wheel 23 to complete the drivingconnection between the adjusting mechanism of the regulator indicated at25 and that of the brush yoke indicated at 26. When it is desired toshift the brushes independently of the regulator, the parts 20 and 21are unlocked and the brushes shifted the'desired amount and directionwhich the parts are again locked together for simultaneous Thus, inreversing, the voltage regulator is left in the initial positioncorresponding to that shown'in Fig. 7 while the brushes are shiftedthrough the angle 12-O12 to give them 'the same relative angle of leadthat they had before the direction of rotation of the motor wasreversed. Now, to increase the speed in the new dlrection of rotation,1t is-only necessarv to simultaneously move the brush yoke and regulator1n the same direction and in and rotor mechanically similar to insprovides for the convenient speed and 'otation over the complete rangeof speeds and below s chronisni. it it is de sued to limit thecoiupersition to that pro- (lhLCf. by the regulator alone, the should 3emoved through 180 while the regulator nioied through 360, in which useno relatire adjustment of the two parts of the adjustin inechawill be ncessary when re e" the direction of rotation of the motor.

The adjustable coupling between the tvo parts of the regulatinginechanisin allows either the brushes, or the regulator to be adjustedalone, or in any desired relation to each other so as to take care otspecial o erating conditions. As shown in Fig. 8 the voltage regulator1e may be built with stator that of an ordinary dyna no electricmachine. The winding 16, 1, will preferably be placed in the stat r. Tie brushes 12 ot' the iii r are coiinectec. to one end of this windingleads 2". The other end of this winding i connected to suitable voltagetaps on the primary winding of the inoto 1 bv leads 2i and to thewinding 15 (Fig. l). which is on the rotor or" the regulator, by leads2S and slip rings 29. Ihe rotor shaft 30 is secured to the adjustinginechanisin either dircctl o" througl a load responsive couplingrepresented at 31. Tiis feature of the invention will now be explainedin coiinei'rtion lth Figs. 8, 9, 10 and 1].

Particularly in the sub-synchronous speed age of operation an increasein load will 'linaril cause he speed to dr p undesir- Jlv without anvidjustnien of the regulating mechanism. To 0011 3 1e. Ior this, advantage is talrcn ot' the increase in torque between the two parts ofthe voltage regulator due to increase in its load uri'eiit to cause l can additional adjustment between regulator and brush shittingineclia'iisni which is automatically proportional to load. i 13 shown in8 and 9 there is a spring 31 between the haft 30 of the regulator andthe adjusting wheel 32. This spring is ctntained in a sector s iapedcasing 33 eyed to the shaftand is con'ipressed between an abutment thiscasing and an i therein from the adjusting wheel 32 in th (TIC netic fluot' the regulator. Vfith the present connection the regulator has in themaximum sub-synchronous speed range a maxiiiiuin value of torque in thedirection represented by the arrow 35, Fig. 10. At synchronous speedthis torque is zero and at SUPQF-SyHOlH'OIiOUS speed it is reverset asrepresented by the arrow liloreorcr, this torque is proportional to theload.

How is it seen that whei the regulator tends to more in the direction oiar'or 35 with respect to the wheel the u will. be compressed to anQlitillt e upon the load and the voltage prod ice-u by the regulatorwill be altered, thereby allowing more current to flow in the eecondarvcircuit of the motor which tends to prevent "lie speed twin tailing theload is inin the sub-synchronous operating unge. jrt light loads thetorque oi the reguator will not compress the spring to any ap-)i'ociable extent. arrangement way interferes with the simultaneous ingniechanisin, nor will it produce desirable displacement at synchroncu"supei s *nchronous speeds since at ...ch nous speed the regulator torqueis zero a supersynchronous speeds the regulate torque is in suchdirection to maintain the abutnient 3% against the ri it hunt. end ofthe spring slot so that for these speeds the driving connection isfixed, but for sub CY chronous speeCs this driving connect flexible andproduces compensation tendi to prevent drop in speed with lli(fi':ir-.l3 load.

The flexible adjustment, which is responsive both to load and to thesub-s"nchronohe speed adjustment below synchroii ii, duces theimprovement represented in 11. Here the abscissa line 0 3th repi-e thedisplacement of the voltage re and the ordinates 0Sl2"- represent thedisplacement of the brushes with corresponding speeds, 12*, S and 12being brush positions corresponding to si b-s vnchronous, syncroiiousandsuper-syichronous speeds, respectively.

The curve N represents the nature of the speed variation forcorresponding various positions of the regulating apparatus at no loadon the motor, and L the corresponding creased accordance with ininvention, the curve :i i-

modified to th/ extent shown in dotted lines at C suchthat'there is nodrop in speed at all between'no load and tull'load for: the fullsub-synchronous speed adjustment. v V In accordance with the provisionsof the patent statutes, I have described the principle of operation ofmy invention, together with the apparatus which I now consider torepresentthe best embodiment thereof; but I desire to have it understoodthat the apparatus shown and described is only illustrative andthat theinvention may be carried out by other means. 7

ll hat I claim as new and desire to secure by Letters Patent ot theUnited States, is:

1. In combination, an alternating current connnutator motor providedwith adjustable brushes, an induction regulator connected to supplyregulating voltages to said brushes, and means for simultaneouslyadjusting said regulator and brushes to vary the speed of said motor,the position of the brushes with respect tothe regulator and theadjusting ratio between them being such as to provide power factorcompensation by brush displacementat speeds removed from synchronism andby the voltage regulator in the synchronous operating range.

2. In combination, an alternating current commutator motor provided withidjustable ln ushes, an induction regulator connected' to supplyregulating voltages to said brushes, and means tor simultaneouslyadjusting said regulator and brushes to vary the speed of said motor ina manner to provide power factor compensation, and means whereby saidbrushes may be adjusted independently or the adjustment of saidregulator.

3. In combination, a reversible alternating cur enti S connected tosupply regulating voltages to s; brushes, and means for sin'iultanouslyad usting said regulator and brushes to 'ary the speed or said motor ina manner to provide power factor compensation in either direction ofrotation, a portion of'whic h compensation is obtained by brushdisplacecommutator motor provided with ment, and means whereby saidbrushes may be adjusted independently of said regulator to providetorthe reversing ot the angle of brush displacement whenthe motor is re-7 versed. V

i. In combination, an alternating commutator motor provided withadjustable brushes, an induction regulator connected to supplyregulating voltages to said brushes, means for simultaneously adjustingsaid regulator through 360 electrical degrees and said brushes throughless than 180 electrical degrees to vary the speed of said motor througha speed range lrom above to below synchronism while maintaining powerfactor compensation in either direction of rotation, and means wherebysaid brushes may beadjusted independently of said regulator tablebrushes, an induction regulator to obtain the desired relation betweenthe brushes and regulator when the motor is reversed.

5. In combination, analt-ernating current commutator motor provided withadjustable brushes, an induction regulator connected to supply speedregulating voltages to 7 said brushes, said regulator being designed toproduce two relatively rotatable voltage vectors which are unequal, andmeans for impressing the ClliIGlGDCG of said voltages upon the brushesat approximately synchronous speed to provide power factor compensation.

6. In combination, an alternating current for changes in speed due-tochanges in load.

8. An alternating current motor, an induction regulator connected tosupply regulating voltages to said motor, manual means for adjustingsaid regulator, andmeans responsive to the torque oi said regulator inone direction only for altering said first mon- I tioned adjustment;

9. In combination, an alternating current commutator motor provided'withadjustable brushes, an induction regulator connected to supplyregulating voltages to said brushes, common adjusting means for saidregulator and brushes for regulating the speed of said motortrom aboveto below synchronism, and means responsive to the load on said regulatorwhen the latter is operating below synchronism for altering theadjustment of said regulator independently of the adjustment of thebrushes in a direction tending to in- 1 crease the speed of the motor.

10. In combination, analternat-ing current commutator motor providedwith .ad-

j ustable brushes, an induction regulator connected to supply regulatingvoltages to said brushes, manually controllable meanstor si-.multaneously adjusting said brushes and regulator, manually controllablewhereby said brushes may be adjusted independently of said regulator,and automatic means responsive to the load on said motor for adjustingsaid regulator independently of saidbrushes. i l

In witness whereof, I have hereunto set myhand this 7th day ofSeptember, 1926. V lVIIiI-IELM lVELSCI-I.

